6.1Ratios, Proportions, and Scale Factors
Quick Answer
A ratio compares two quantities; a proportion sets two ratios equal. Scale factor is the ratio of corresponding lengths in similar figures. Cross-multiplication solves proportions.
Essential Question
How do ratios and proportions provide the algebraic foundation for all similarity relationships in geometry?
Learning Goals
- 1Write and simplify ratios.
- 2Set up and solve proportions using cross-multiplication.
- 3Identify scale factors between similar figures.
- 4Apply proportions to find missing lengths.
Key Vocabulary
Ratio
A comparison of two quantities by division.
Proportion
An equation stating that two ratios are equal.
Scale factor
The ratio of corresponding lengths in two similar figures.
Full lesson content coming soon
Worked examples, guided practice problems, a workbook, quiz, and downloadable PDF resources will be added to this lesson in Phase 2. The learning goals and vocabulary above reflect the complete lesson scope.